The use of touch-sensitive surfaces as input devices for computers and other electronic computing devices has increased significantly in recent years. Example touch-sensitive surfaces include touchpads and touch-screen displays. Such surfaces are widely used to manipulate user interfaces and objects therein on a display. Example user interface objects include digital images, video, text, icons, and control elements such as buttons and other graphics.
Electronic computing devices often display virtual controls or visual guides on their displays. For example, keyboards, menus, dialog boxes, alerts, and other controls be activated and manipulated (e.g., by touch inputs) that cause operations to be performed on a portable electronic device (e.g., a smart phone, tablet, or notebook computer). Indicators and visual guides may be overlaid on a background (e.g., a user interface of an application or a user interface of the operating system) that provide visual cues regarding the types of inputs that may be provided and/or the types of operations that may be performed in association with particular regions of the background or screen.
Existing methods for displaying controls, indicators, and visual guides may be cumbersome and inefficient. For example, the controls, indicators, and visual guides may create unnecessary distractions to the user when the user manipulates the user interfaces, or are not sufficiently clear or salient against a background, causing user mistakes and user confusion when the user interacts with the devices, which, additionally, negatively affects the energy consumption of the devices. This latter consideration is particularly important in battery-operated devices.
Furthermore, certain types of affordances that are displayed over a wide variety of background and content and sometimes over extended time without movement. Consequently, the displays can exhibit ghost-images (or burn-ins) of the affordances after having been in use for some time. Reduction and elimination of display burn-ins is a long-standing challenge facing the display device manufacturers. Some existing ways of addressing the issue, such as introducing screen savers or shimmering icons, are less than satisfactory solutions, due to their side effects (e.g., causing eye strain, distraction, etc.) and lack of efficacy in many scenarios (e.g., usable only when device is idle).